| 摘要 |
PURPOSE:To accurately evaluate fine particles in a liquid by flowing a sample liquid in a transparent narrow tube to form a certain flow passage and projecting a laser light to the narrow tube in the vertical direction and detecting the diffracted light and the scattered light due to fine particles in the liquid by a Fourier transform optical system. CONSTITUTION:The light from a laser oscillator 2 is not only expanded but also converted to parallel rays of a luminous flux by a beam expanding system 3. A Fourier transform lens 5 is arranged on the opposite side of a narrow tube 4, and a scattered pattern evaluating semiconductor detector 6 is set on the focal surface of the lens 5. Washing water including fine particles 9 flows from the upper flow passage and traverses the laser light at right angles. A diffracted and scattered pattern 7, which is generated when fine particles 9 pass the center part of the wide projected light, is received by a photodetector 6. The photodetector 6 consists of light receiving areas having concentricity and directivity, and an address code is given to each light receiving area, and the output condition from an optional element is unequivocally determined. Consequently, signals from concentric light receiving areas are analyzed to obtain an extreme value of the intensity distribution expressed with the Bessel function, and the particle size is determined. |
